1. Field of the Invention
The present invention relates to a hollow golf club head, and particularly to a golf club head being of a wood type or similar type thereto.
2. Description of the Related Art
As wood-type golf club heads such as drivers and fairway woods, metallic heads of a hollow shell structure are widely in use. Generally, the hollow wood-type golf club head has a face portion for hitting a ball, a crown portion constituting an upper surface portion of the golf club head, a sole portion constituting a bottom surface portion of the golf club head, a side portion constituting side surface portions on the tow side, the rear side, and the heel side of the golf club head, and a hosel portion. A shaft is inserted into the hosel portion, and is fixed by an adhesive agent or the like. It should be noted that golf clubs called utility clubs are also commercially available on the market in large numbers, and various golf clubs having ahead similar to the aforementioned wood-type golf club head (i.e., having the face portion, the sole portion, the side portion, the crown portion, and the hosel portion) are also commercially available on the market.
As metals for forming this hollow golf club head, an aluminum alloy, stainless steel, and a titanium alloy are used. The titanium alloy, in particular, has come to be used widely in recent years (refer to JP-A-2003-88601).
Generally, it becomes possible to enlarge the sweet spot by increasing the volume of the hollow golf club head. If the volume is increased, the weight of the golf club head tens to increase correspondingly. Accordingly, to prevent an increase in the weight, a thickness of a shell portion of the golf club head has been made thin.
To have a center of gravity of the golf club head at lower position, a weight member has been mounted on the sole portion.